t thomas meadoo



(No Model.)

T. MQ'ADOO.

ELEVATOR.

"Patentd Fe b. 5,1884.

INVENTOR Thoma: Ma 5 100 WITNESSES:

A ATTORNEYS @ATENT Er ch.

"rn'oMi-is MQADOO, onnnwvorni, it; Y.

ELEVATOR.

SPECIFIQATION forming part ofLetters Patent No. 293,050, dated February5, 1884.

Application filed Julyfll, 1883. (No model.)

To all whom it 17mg concern:

tion.

This invention relates to a check for an elevator-car which allows thecar to ascend freely, while it prevents said car in its descent fromfalling or from moving with an undue velocity."

The peculiar and novel construction of my check is pointed out in thefollowing specification and illustrated in the accompanying drawings, inwhich Figure 1 represents a horizontal section of the check mechanism inthe plane a m, Fig. 2. Fig. 2 is a longitudinal vertical section in theplane y y, Fig. 1.

Similar letters indicate corresponding parts.

This check mechanism is secured to the bottom of the car, which moves upand down between the vertical posts A A. Said check mechanism consistsof two cylinders, B B, which are open at their inner ends,while theirouter ends are connected by a U-shaped-pipe, 0. Each of the cylinders isprovidedwith a piston, D D, respectively, and a small tube,

E, extendsfrom one cylinder to the other, said tube being situated nearthe outer ends of the cylinders, as shown in the drawings.

In the interior of the pipe 0 is situated a check-valve, F, which openswhen the piston D moves inward, and which closes when the piston D movesinward. Said pistons move in opposite directions, and a reciprocatingmotion is imparted to them by means of eccentrics G G, which are mountedon a shaft, H.

Instead of eccentrics, I can employ cranks or other equivalent means.

The shaft H has its bearings in hangers I, which are firmly secured tothe bottom of the car, and on the outer ends of said shaft are firmlymounted worm-wheels J J. ,which gear into worms K K, mounted on shafts LL.

These shafts have their bearings in hangers l\I M,wl1ich are secured tothe bottom of the car, and on said shafts are mounted cog-wheels NN,which engage with toothed racks 00, fastened to the vertical posts A Aand extending from the bottom of the elevator-well to its top.

The cylinders BB and the pipe 0 are charged with a suitable liquid-suchas glycerine-and when the car is clear down the pistons DD occupy thepositions shown in Fig. 1, the piston D being at the outer and thepiston D at the inner end of its stroke. WVhen the elevator-car i sraised up the cog-wheels N N revolve,

and a slow revolving motion is imparted to V the shaft H, so that thepiston D is forced i11- ward, while the piston D moves outward.

During the upward motion of the car, therefore,the liquid contained incylinder B and in the pipe 0 is gradually forced into the cylinder B,and since the check-valve F opens,when the piston D moves inward, fioperceptible 0bstruction is producedby the liquid. The motion of thepistons D D.is so gaged that when the elevator car has moved clear up tothe top of the well the piston D .has reached theinner When the cardescends, the piston D moves i11- ward and the piston D outward, thecheck valve F closes by the pressure of the liquid on its back, and theliquid which is gradually displaced from the cylinder Bwhilethe piston Dmoves inward has to pass through the small tube E in order to reach thecylinder 13. The liquid therefore creates a material obstruction to thedownward motion of the car, and it will be readily seen that, even iftheropezfromwhich the car is suspended should break,-the downward motionof the car will be checked to such an extent that no accident canhappen.

The tube E may be provided with a cock, so that the flow of the liquidthrough said tube can be regulated, and by closing this stop-cock thedownward motion of the car canbe arrested. It must also be remarked thatthe mechanism for imparting to the pistons D Da reciprocating motion inopposite directions can be modified in various ways, and I do not wishto conline myself to the exact mechanism shown in the drawingstbut thismechanism will give a good result, it is easily applied, and not liableto get out of order. p

What I claim as new, and desireto secure by Letters Patent, is-,

1. The combination, substantially as hereinbefore described, with anelevator-car, of two cylinders fastened to the car, the pipe 0, and

the tube E, connecting said cylinders, the check-valve in the pipe 0,the pistons moving in the two cylinders, and suitable mechanism .7 andthe piston D the outer end of its stroke.

for imparting to the pistons a reciprocating shaft H, and suitable meansfor transmitting v motion in opposite directions. motion from the shaftH to thepistons D D.

2. Theeombination, substantially as herein- In testimony whereof I havehereunto set before described, with an elevator-car, of two my hand andseal in the presence of two sub- 5 cylinders fastened to the bottom ofthe car, the scribing witnesses, pipe 0, and tubeE connecting saidcylinders,

the check-valv'ein the pipe 0, the pistons mov- THOS' MOADOO' ing in thetwo cylinders, the toothed racks se- \Vitnesses: cured to the posts A A,the cog-wheels N N, JOHN Monnis, 1O shafts L L, worms K K, worm-wheels JJ, 'CHAS. VVAHLERs.

